Lithium-based alloy and method of producing the same

ABSTRACT

A lithium (Li)-based alloy and a preparation method thereof are disclosed, in which the lithium metal is wrapped by a metal foil with a higher melting point, followed by subjecting to multi-stage thermal treatment to cast alloy, thereby obtaining the Li-based alloy with high purity-Li.

RELATED APPLICATIONS

This application claims priority to Taiwan Application Serial Number099141471, filed Nov. 30, 2010, which is herein incorporated byreference.

BACKGROUND

1. Field of Invention

The present invention relates to a lithium (Li)-based alloy and a methodof producing the same. More particularly, the present invention relatesto a lithium (Li)-based alloy with high purity-Li and a method ofproducing the same.

2. Description of Related Art

Lithium (Li)-based alloy is generally referred to a lightweight alloymaterial including Li. Due to Li with extremely low density (0.534g/cm³), the Li-based alloy has lower density as compared to other kindsof alloys. Recently, the Li-based alloy becomes the prime candidatematerial for designing lightweight structural devices.

Typically, vacuum induction melting (VIM) process is commonly applied tocast the Li-based alloy, and it is generally divided into forward feedcasing process and reverse food casting process. During the forward feedcasing process, low-melting-point Li is molten in a highly vacuumedchamber of the VIM furnace with nitrogen gas introduced therein, andthen the molten Li is heated to a higher temperature and added withother higher-melting-point metal, so as to cast the Li-based alloy. Onthe contrary, during the reverse feed casing process, otherhigher-melting-point metal is molten in a highly vacuumed chamber of theVIM furnace with nitrogen gas introduced therein, and then it is addedwith low-melting-point Li, so as to cast the Li-based alloy.

In addition, mechanical alloying process is also applied to cast theLi-based alloy, in which Li and Al metals are ball milled for a longperiod, so as to form β-phase Li—Al alloy (or β-Li—Al alloy).

However, it is hardly to avoid the overheating conditions when using theaforementioned processes. Li is an active element and has lower meltingpoint and density. During casting alloy in the conventional processes,the molten Li is easily floated on the molten Al, so that it hardlyprevents the molten Li from being evaporated in the overheatingcondition and generating undesired Li oxides or impurities. Thus, it ismore difficult to cast Li—Al alloy during the conventional processes,and the resulted Li—Al alloy has low purity Li, oxides and impurities.

Hence, it is necessary to provide a Li-based alloy and a method ofmaking the same, thereby overcoming the disadvantages of evaporation,oxides or impurities of lithium during the conventional processes suchas forward feed casing process, reverse food casting process andmechanical alloying process.

SUMMARY

According to an aspect of the invention, a method of producing lithium(Li)-based alloy is provided. The method of producing lithium (Li)-basedalloy comprises the steps of wrapping lithium metal by using a metalfoil with a higher melting point, followed by subjecting to multi-stagethermal treatment to cast alloy, thereby obtaining the Li-based alloywith more uniformly dispersed and high purity-Li. Since the method cansave the total process time and reduce the occurrence of evaporation,oxides or impurities of lithium. Therefore, the present method overcomesthe troubles of evaporation, oxides or impurities of lithium during theconventional processes such as forward feed casing process, reverse foodcasting process or mechanical alloying process.

Moreover, a Li—Al alloy is further provided, which has more uniformlydispersed and high purity-Li is casted by the aforementioned method.Therefore, the Li—Al alloy can be applied on the lightweight structuraldevices (e.g. materials of sports equipments or cases of military weaponcases) or composite hydrogen-storage materials.

Accordingly, the invention provides a method of producing Li-basedalloy. In an embodiment, a lithium metal is firstly wrapped by using ametal foil for forming a wrapped lithium metal. In an example, the metalfoil includes a material of a high-melting-point metal having a highermelting point than a melting point of the lithium metal.

Next, a raw material and the wrapped lithium metal are heatedrespectively to a first temperature. In an example, the raw materialincludes the same material of the high-melting-point metal as the metalfoil, and the first temperature may be between the melting points of themetal foil and the lithium metal.

And then, the wrapped lithium metal is mixed with the raw material atthe first temperature, so as to form a metal mixture, followed byheating the metal mixture to a second temperature, in which the secondtemperature is higher than the melting point of the high-melting-pointmetal, so as to form an molten alloy. Afterward, the molten alloy ismixed at the second temperature.

Subsequently, the alloy is cooled down for forming a lithium-basedalloy, in which the lithium-based alloy is a β-phase lithium-basedalloy, and the lithium metal has a weight loss rate of equal to or lessthan 1 percent.

According to an embodiment of the present invention, thehigh-melting-point metal may include but not be limited to aluminum,magnesium, manganese, zirconium, zinc, titanium, scandium, yttrium,copper, silver or any combination thereof.

According to an embodiment of the present invention, the raw materialmay further comprise a non-metal material including silicon.

According to an embodiment of the present invention, the raw materialmay further comprise another metal that includes a different materialfrom the high-melting-point metal. In an example, the first temperaturemay be between two lower melting points of the lithium metal, thehigh-melting-point metal and the another metal. In another example, thesecond temperature may be higher than the highest melting point of thelithium metal, the high-melting-point metal and the another metal.

According to another aspect of the present invention, a β-phase Li—Alalloy (or β-Li—Al alloy) is further provided. In an embodiment, theβ-Li—Al alloy may be casted by any one of the aforementioned methods. Inanother embodiment, the β-Li—Al alloy may be applied on the lightweightstructural devices or composite hydrogen storage materials.

With application of the Li-based alloy and the method of making thesame, the lithium metal is wrapped by using the metal foil with a highermelting point, followed by subjecting to multi-stage thermal treatmentto cast alloy, thereby obtaining the Li-based alloy with more uniformlydispersed and high purity-Li. Since the present method can save thetotal process time and reduce the occurrence of evaporation, oxides orimpurities of lithium, it successfully overcomes the troubles ofevaporation, oxides or impurities of lithium during the conventionalprocesses such as forward feed casing process, reverse food castingprocess or mechanical alloying process, thereby being applied on thelightweight structural devices (e.g. materials of sports equipments orcases of military weapons) or composite hydrogen storage materials.

It is to be understood that both the foregoing general description andthe following detailed description are by examples, and are intended toprovide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the followingdetailed description of the embodiment, with reference made to theaccompanying drawings as follows:

FIG. 1 depicts a flow chart diagram of the method of producing aLi-based alloy according to an embodiment of the invention; and

FIG. 2 depicts a diagram of a reacting system according to an embodimentof the invention.

DETAILED DESCRIPTION

As aforementioned, the present invention provides a Li-based alloy and amethod of producing the same, in which the low-melting-point lithiummetal is wrapped by using metal foil that is made from ahigh-melting-point metal having a higher melting point than lithium (orcalled as a high-melting-point metal foil). Following, the wrappedlithium metal is subjected to a multi-stage thermal treatment to castalloy, thereby obtaining the Li-based alloy with more uniformlydispersed and high purity-Li. It should be clarified that the “Li-basedalloy” is referred to a lightweight alloy material including the lithiummetal. The “metal foil” herein may include but not be limited to a metalfilm, a metal sheet and other structural equivalents or alternatives.

Composition of Li-Based Alloy

In an embodiment, the Li-based alloy may be consisted of two metalmaterials such as lithium metal and a high-melting-point metal. Thehigh-melting-point metal has a higher melting point than the lithiummetal, which may be exemplified as but not limited to aluminum,magnesium, manganese, zirconium, zinc, titanium, scandium, yttrium,copper or silver, thereby forming Li—Al, Li—Mg, Li—Mn, Li—Zr, Li—Zn,Li—Ti, LiSc, Li—Y, Li—Cu or Li—Ag alloys. In an example, the Li-basedmay be Li—Al alloy, for example. In another example, the Li-based alloymay be also a β-phase Li—Al alloy (or n-Li—Al alloy).

In another embodiment, at least a third material may be alternativelyadded into the Li-based alloy that includes the aforementioned two metalmaterials, so as to form a Li-based alloy that includes at least threecomponents. The third material may be a metal or non-metal material.When the third material is a metal material, it may be anotherhigh-melting-point metal that is different from the aforementioned twometal materials or other metal material. When the third material is anon-metal material, it may be silicon, for example.

Method of Making Li-Based Alloy

Since the lithium metal is easily oxidized and evaporated due to itslower melting point (approximately 180.54° C.), the present invention isdirected to wrap the lithium metal by using a high-melting-point metalfoil, thereby reducing the period of lithium oxidization andevaporation.

Reference is made to FIG. 1, which depicts a flow chart diagram of themethod of producing a Li-based alloy according to an embodiment of theinvention. The method 100 may include but not be limited to amulti-stage thermal treatment to cast alloy. Hereinafter, the Li-basedalloy produced by two components is firstly exemplified as follows.

At first, in the step 101, the lithium metal is wrapped by using a metalfoil for forming a wrapped lithium metal. In an example, a material ofthe metal foil may be a high-melting-point metal having a higher meltingpoint than the lithium metal as exemplified as aforementioned.

Next, in the step 103 (or a first heating step), a raw material and thewrapped lithium metal are heated respectively to a first temperature. Inan example, the raw material includes the same material of thehigh-melting-point metal as the metal foil, and the first temperaturemay be between the melting points of the metal foil and the lithiummetal. Moreover, at the first temperature, the lithium metal must bemolten but the high-melting-point metal is heated uniformly and close toa being-molten state, so that the high-melting-point metal can protectthe molten lithium metal from being evaporated and oxidized. Thus, in anexample, the first temperature is higher than the melting point of thelithium metal but lower than the one of the high-melting-point metal.

In another example, when the high-melting-point metal is aluminum metalthat has a melting point of approximately 660° C., the first temperatureis about 200° C. to less than 660° C., or about 630° C. to about 650°C., or alternatively 640° C.

For the purpose of decreasing the probability of the Li oxidation, inthe step 103, the reacting chamber can be filled with a protection gasor under vacuum. In an example, when the reacting chamber is filled witha protection gas, the protection gas may be nitrogen gas or other inertgases, and an internal pressure may be more than one atmosphere (atm),for example. In other examples, when the reaction chamber is undervacuum, the internal pressure may be less than approximately 10⁻² Torr(i.e. approximately 1.33 Pa), for example.

In order to reduce the subsequent time of Li oxidation and evaporation,the step 103 can be carried out in the aforementioned conditions forabout one hour.

And then, in the step 105, the wrapped lithium metal is mixed with theraw material at the first temperature, so as to form a metal mixture. Inan example, the pre-heated high-melting-point metal may be added intothe pre-heated wrapped Li metal, for forming the metal mixture.Following, in the step 107 (or a second heating step), the metal mixtureis heated to a second temperature, in which the second temperature ishigher than the melting point of the high-melting-point metal, so as toform a molten alloy. For completely melting the high-melting-point metaland the Li metal to form the molten alloy, the second temperature isnecessarily higher than the melting point of the high-melting-pointmetal. According to an embodiment, the second temperature may be 80° C.to 100° C. higher than the melting point of the high-melting-pointmetal.

Afterward, in the step 109, the molten alloy is mixed well at the secondtemperature. Subsequently, in the step 111, the molten alloy is cooleddown for forming a lithium-based alloy. In an example, the molten alloymay be cooled down to 0° C. to 50° C. approximately.

Due to the low-melting-point Li metal wrapped with thehigh-melting-point metal foil, followed by the multi-stage thermaltreatment to cast alloy, the preset method can produce the Li-basedalloy with more uniformly dispersed and high purity-Li in mass in ashorter process time (4 to hours approximately), in which the Li-basedalloy is a β-phase lithium-based alloy, and the lithium metal has aweight loss rate of equal to or less than 1 percent.

It is worth mentioning that, instead of directly heating to the secondtemperature in the prior process, the present method reduces thedifference between the first and second temperatures in the step 107because the Li metal contacts with the being-molten high-melting-pointmetal prior to contacting with the protecting gas. Hence, it drasticallydecreases the probability of the impurities since the Li metal is hardlyto contact with the impurities in the protecting gas. Moreover, it alsoreduces the evaporation time of the Li metal due to the high thermaltreatment.

Furthermore, the Li-based alloy may be produced by at least threecomponents, and in this case, the at least three components may includebut be not limited to the Li metal, the high-melting-point metal and athird material. The third material may be another metal or a non-metalmaterial.

In addition, the Li-based alloy produced by the at least threecomponents may be obtained by using the aforementioned method. Forexample, in the step 101, the lithium metal is wrapped by a metal foilfor forming wrapped lithium metal, in which the metal foil includes amaterial of the high-melting-point metal.

Next, in the step 103, the wrapped lithium metal and a raw materialconsisting of the high-melting-point metal and the third material areheated respectively to a first temperature. In an example, the firsttemperature may be the first temperature is between two lower meltingpoints of the lithium metal, the high-melting-point metal and the thirdmaterial.

Following, in the step 107, the second temperature is higher than thehighest melting point of the lithium metal, the high-melting-point metaland the third material, or the second temperature may be 80° C. to 100°C. higher than the highest melting point of the lithium metal, thehigh-melting-point metal and the third material.

It should be supplemented that, during producing the Li-based alloy withthe at least three components, only the Li metal is wrapped by thehigh-melting-point metal, but the third material doesn't be wrapped.

Reacting System for Producing Li-Based Alloy

Reference will now be made in detail to the present embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers are used in thedrawings and the description to refer to the same or like parts.

In an embodiment, the method of making the Li-based alloy can be carriedout in conventionally reacting system or the reacting system 200 of FIG.2. Hereinafter, the reacting system 200 of FIG. 2 is exemplified toclarify this disclosure. Reference is made to FIG. 2, which depicts adiagram of a reacting system according to an embodiment of theinvention. In an embodiment, the reacting system 200 of FIG. 2 may be astep-controlled casting furnace, for example. The aforementioned step101 may be carried out in two reacting chambers such as a pre-heatcrucible 211 and a main crucible 212 of the reacting system 200 of FIG.2, in which the main crucible 212 is connected to a side of the pre-heatcrucible 211.

The pre-heat crucible 211 is used for receiving the high-melting-pointmetal 218 (e.g. aluminum or at least two different high-melting-pointmetals). Heating devices 223 may be disposed on an outside of thepre-heat crucible 211 for performing the aforementioned first heatingstep (e.g. the step 103), for pre-heating the high-melting-point metal218 uniformly in the pre-heat crucible 211 to the first temperature. Themain crucible 212 is used for receiving the Li metal 220 wrapped by thehigh-melting-point metal foil 219. There are also heating devices 203disposed on an outside of the main crucible 212 for performing themulti-stage thermal treatments such as the first heating step (e.g. thestep 103), the second heating step (e.g. the step 107), the mixing stepat the second temperature (e.g. the step 109), the cooling step (e.g.the step 111) and so on.

The Li metal has a very lower melting point than the high-melting-pointmetal 218, that is to say, it is longer for heating thehigh-melting-point metal 218 to the first temperature. However, duringthe first heating step, the high-melting-point metal 218 heated in thepre-heat crucible 211 may generate radiant heat for melting the Li metal220 probably. Thus, in an embodiment, a heat-insulation material, forexample, the heat-insulation plate 215 of FIG. 2, may be disposedbetween the pre-heat crucible 211 and the main crucible 212 of thereacting system 200. The heat-insulation plate 215 may be made ofrefractory fibers, so that it can prevent the heat of the pre-heatcrucible 211 from radiating to the main crucible 212, thereby avoidingthe Li metal 220 to melt too early. Besides, an opening 215 a optionallydisposed on the heat-insulation plate 215 may be corresponded to alowering position of a mixing bar 214, so that the mixing bar 214 canpass through the opening 215 a and extend into the main crucible 212 forstirring and mixing the molten alloy.

When the Li metal 220 wrapped by the high-melting-point metal foil 219in the main crucible 212 is heated to the first temperature by using theheating devices 203, the high-melting-point metal 218 is also heateduniformly and close to a being-molten state. In the meanwhile, by usinga pushing bar 213 along a direction of an arrow 231, the pre-heatedhigh-melting-point metal 218 is pushed into the Li metal 220 wrapped bythe high-melting-point metal foil 219 in the main crucible 212, followedby heating to the second temperature by using the heating devices 203,and allowing both of the high-melting-point metal 218 and the Li metal220 wrapped by the high-melting-point metal foil 219 to form a moltenalloy.

Later, the mixing bar 214 can pass through the opening 215 a, extendinto the main crucible 212, stir and mix the molten alloy in the maincrucible 212 along a direction of an arrow 233, so as to make allcomponents more uniformly. In an example, the mixing bar 214 can be madeof a heat-resistant material such as stainless, and a refractorymaterial can be coated on a surface of the mixing bar 214. In anotherexample, the mixing bar 214 can be disposed above the main crucible 212and fixed on a side of the reacting system 200 by using an 0-ring. Themixing bar 214 can be operated along upward, downward, clockwise orcounterclockwise direction for stirring and mixing the molten alloyuniformly.

During the cooling step (e.g. the step 111), the molten alloy can becooled down naturally for forming the Li-based alloy.

Reference is made to FIG. 2 again. In an embodiment, during performingthe aforementioned multi-stage thermal treatment, at least one gas inlet216 and a gas outlet 217 can be disposed on a backside of the reactingsystem 200, for providing a higher vacuum environment or an environmentfilled with the protection gas. In an example, the gas inlet 216 can bedisposed on any position freely depending on the casting requirements,and it can be connected with a gas bottle for introducing the protectiongas from an opening 205 into the reacting system 200. In this example, aball valve (unshown) can be disposed at a connection site of the gasinlet 216 connecting with the reacting system 200, for controlling thetransfer of the protection gas. In another example, the gas outlet 217can be connected with a mechanical pump (unshown) to vacuum the innerchamber (e.g. the pre-heated crucible 211 and the main crucible 212) ofthe reacting system 200 from an opening 207 for achieving a vacuum orhighly vacuum state. In this example, another ball valve (unshown) canbe also disposed at a connection site of the gas outlet 217 connectingwith the reacting system 200, for controlling the vacuum degree.

Since the metal foil with the higher melting point than the Li metal isused to wrap the Li metal in the present method, followed by subjectingto the multi-stage thermal treatment to cast alloy, thereby saving thetotal process time and drastically reduce the occurrence of evaporation,oxides or impurities of lithium. Therefore, the present methodsuccessfully overcomes the troubles of evaporation, oxides or impuritiesof lithium during the conventional processes such as forward feed casingprocess, reverse food casting process or mechanical alloying process.Moreover, the Li-based alloy has more uniformly dispersed and highpurity-Li, thereby being applied on the lightweight structural devices(e.g. materials of sports equipments or cases of military weapons) orcomposite hydrogen storage materials.

Thereinafter, various applications of the Li-based alloy and the methodof making the same will be described in more details referring toseveral exemplary embodiments below, while not intended to be limiting.Thus, one skilled in the art can easily ascertain the essentialcharacteristics of the present invention and, without departing from thespirit and scope thereof, can make various changes and modifications ofthe invention to adapt it to various usages and conditions.

EXAMPLE Preparation of β-Phase Li—Al Alloy

In this example, the β-phase Li—Al alloy was prepared by the reactingsystem 200 of FIG. 2. At first, the aluminum metal and the lithium metalwith the weight ratio of 5:1 were weighted. The aluminum metal waspre-heated uniformly to the first temperature, and the first temperaturewas about 200° C. to about 660° C., or about 630° C. to about 650° C.,or about 640° C. Meanwhile, the Li metal 220 wrapped by thehigh-melting-point metal foil 219 in the main crucible 212 was alsoheated uniformly to the first temperature.

Next, the pre-heated aluminum metal was added into the main crucible212, followed by performing the second heating step to the secondtemperature. The second temperature was about 740° C. to about 760° C.,or 750° C., for completely melting the aluminum metal and the Li metalto form the molten alloy.

Before contacting with the protecting gas, the Li metal contacted withthe being-molten aluminum metal firstly. Hence, it drastically decreasedthe probability of the impurities since the Li metal was hardly tocontact with the impurities in the protecting gas. Moreover, since thealuminum was pre-heated before being molten, it reduced the heating timeof the main crucible 212 and the evaporation time of the Li metal underthe high thermal treatment.

Afterward, the molten alloy was mixed well at the second temperature forapproximately 10 minutes.

Subsequently, the molten alloy was cooled down to 0° C. to 50° C.approximately for forming the β-phase Li—Al alloy. The aforementionedprocess time was spent only about 4 to 5 hours.

The content of the resulted β-phase Li—Al alloy was further analyzed bya commercially available equipment, for example, inductively coupledplasma—atomic emission spectrometer (ICP-AES), for obtaining the resultas shown in TAB. 1. According to the result of TAB. 1, the content ofthe cast β-phase Li—Al alloy was very close to the theoretical ratios,and the total casting process was spent only about 4 to 5 hours.

TABLE 1 Content of Elements in Li—Al alloy (wt. %) Li Al Fe Mn Cr O 19.880.01 0.10 0.02 0.03 0.04

It is worth mentioning that, the aluminum foil with the higher meltingpoint is used to wrap the Li metal in the present method, followed bysubjecting to the multi-stage thermal treatment to cast alloy, therebysaving the total process time (about 4 to 5 hours) and producing theLi-based alloy with more uniformly dispersed and high purity-Li in mass.Additionally, the lithium metal has a weight loss rate of equal to orless than 1 percent. Therefore, the present method successfullyovercomes the troubles of evaporation, oxides or impurities of lithiumduring the conventional processes such as forward feed casing process,reverse food casting process or mechanical alloying process.

The resulted Li-based alloy can be applied on any type of thelightweight structural devices or composite hydrogen storage materials,which include but not are limited to materials of sports equipments,cases of military weapons or composite hydrogen storage materials,rather than describing in detail herein. However, it is necessarilysupplemented that, some technical details such as specific kinds orratio of metals, specific processing conditions, specific equipments andspecific analyzing methods are employed as exemplary embodiments in thepresent invention, for obtaining and evaluating the applications of theresulted Li-based alloy. However, it is not necessary to use allaforementioned details in all embodiments. As is understood by a personskilled in the art, the Li-based alloy of the present invention caninclude other kinds or ratio of metals, other processing conditions,other equipments and other analyzing methods rather than limiting to theaforementioned examples. Moreover, all known structure or devicesfamiliarly to the person skilled in the art are merely depictedschematically in the accompanying drawings for illustration purposesonly.

According to the embodiments of the present invention, the Li-basedalloy and the method of making the same advantageously include to wrapthe lithium metal by using the metal foil with a higher melting point,followed by subjecting to multi-stage thermal treatment to cast alloy,thereby obtaining the Li-based alloy with more uniformly dispersed andhigh purity-Li. Since the present method can save the total process timeand reduce the occurrence of evaporation, oxides or impurities oflithium, it can be applied on the lightweight structural devices (e.g.materials of sports equipments or cases of military weapons) orcomposite hydrogen storage materials.

As is understood by a person skilled in the art, the foregoing preferredembodiments of the present invention are illustrated of the presentinvention rather than limiting of the present invention. In view of theforegoing, it is intended to cover various modifications and similararrangements included within the spirit and scope of the appendedclaims. Therefore, the scope of which should be accorded the broadestinterpretation so as to encompass all such modifications and similarstructure.

1. A method of producing lithium-based alloy, comprising: wrappinglithium metal by using a metal foil for forming a wrapped lithium metal,wherein the metal foil includes a material of a high-melting-point metalhaving a higher melting point than a melting point of the lithium metal;heating a raw material and the wrapped lithium metal respectively to afirst temperature, wherein the raw material includes the material of thehigh-melting-point metal, and the first temperature is between themelting points of the metal foil and the lithium metal; mixing thewrapped lithium metal with the raw material at the first temperature, soas to form a metal mixture; heating the metal mixture to a secondtemperature, wherein the second temperature is higher than the meltingpoint of the high-melting-point metal, so as to form an molten alloy;mixing the molten alloy at the second temperature; and cooling down thealloy for forming a lithium-based alloy, wherein the lithium-based alloyis a β-phase lithium-based alloy, and the lithium metal has a weightloss rate of equal to or less than 1 percent.
 2. The method of producinglithium-based alloy of claim 1, wherein the high-melting-point metalcomprises at least two different metals of aluminum, magnesium,manganese, zirconium, zinc, titanium, scandium, yttrium, copper, silveror any combination thereof.
 3. The method of producing lithium-basedalloy of claim 1, wherein the second temperature is 80° C. to 100° C.higher than the melting point of the high-melting-point metal.
 4. Themethod of producing lithium-based alloy of claim 1, wherein the rawmaterial further comprises another metal, and the another metal includesa material different from the high-melting-point metal.
 5. The method ofproducing lithium-based alloy of claim 4, wherein the first temperatureis between two lower melting points of the lithium metal, thehigh-melting-point metal and the another metal.
 6. The method ofproducing lithium-based alloy of claim 4, wherein the second temperatureis higher than the highest melting point of the lithium metal, thehigh-melting-point metal and the another metal.
 7. The method ofproducing lithium-based alloy of claim 4, wherein the second temperatureis 80° C. to 100° C. higher than the highest melting point of thelithium metal, the high-melting-point metal and the another metal. 8.The method of producing lithium-based alloy of claim 1, wherein the rawmaterial further comprises a non-metal material.
 9. The method ofproducing lithium-based alloy of claim 8, wherein the non-metal materialcomprises silicon.